Sound-insulating construction



April 15, 1930. B. E. BALDUF SOUND INSULATING CONSTRUCTION Filed Nov. 10, 192'? 2 Sheets-Sheet l W W W m 192'? 2 Sheets-Sheet 2 ZZZ/414%? B. E, BALDUF SOUND INSULATING CONSTRUCTION Filed Nov. 10,

April 15, 1930.

rill/l" Patented Apr. 15, 1930 UNITED STATES PATENT OFFICE BRUNO E. BALDUF, OF CHICAGO, ILLINOIS, ASSIGNOR TO'THE UNITEDSTATES GYP- SUM 00., OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS SOUND-INSULATING CONSTRUCTION This invention relates to a system of sound insulated building construction particularly adapted to prevent the transmission of sound through the plenum chamber in suspended ceiling construction. In constructing a sound insulated building it must be borne in mind that sound is transmitted through the various bodies of the building and through so called dead air spaces which are susceptible to drum or cushion action by vibration only. The three essentials, therefore, to effect insulation against transmission of sound are weight, rigidity and absorption. In all sound insulation systems based on absorptive pads etc.,

weight must be added in some form or other to provide satisfactory insulation against sounds of a prolonged frequency such as bowling balls, moving machinery, etc. Sound forces vibrating or aiming to vibrate a wall or .ceil- :0 ing perform work and so change from asound into heat energy. It is, therefore, the object of this invention to provide a system of sound insulation in which the transmission of sound is prevented either through the solid members employed or through the drum or cushion action of so-called dead air spaces, by means of a fluffy flocculent fireproof fill surrounding and imbedding all structural members, rendering them inert to the transmission of sound and providing the construction with the necessary weight at the same time. This previously described fill is retained by a suitable plaster base preferably plaster board form, which in combination with the arrangement of the structural members the weight of the fill previously described provides the necessary rigidity. One of the most common uses for such a system is in suspended ceilings under theaters having a plenum chamber and where the noises from rooms below the theater would be exceedingly annoying to the patrons.

In the. drawings Fig. 1 is a cross section through a construction of this type;

Fig. 2 is a partially sectionalized plan View. Figs. 3 and 4 are respectively a section and plan of a modification of the construction shown in Figs. 1 and 2.

' The floor in Fig. 1 may be-of any of the usual constructions with clips, hooks or eye bolts (2), inserted as suspensories on the under side. These suspensories support sleeves (3) whicli consist of strips of sheet metal containing a lining of a resilient material. The main suspended ceiling beams l) which may be any form of structural steel rest on these sleeves. Secondary structural members (5) are attached to the main supporting beams (4:) by any suitable means. These secondary beams in turn support the finished ceiling or panel (6) which in the preferred form consists of a plaster board and plaster. Resting upon and attached to the main channel beams (4:) are supports (7), which are separated from the beams by spacers (8) of a resilient material. These supports carry the upper portion (9) of the suspended ceiling. These supports are usually wood when the plenum chamber floor (9) is of a plaster board type, but when tile are used the supports are preferably T bars. To prevent the drum or concussion action Within the suspended ceiling, the space between the finished ceiling (6) and the upper portion or panel of the suspended ceiling (9) is filled with a dry, fluffy, pulverulent fireproof material which is highly sound absorptive. This insulating and filling material is more fully described in appllcants copending application, Serial 107,797, filed May 8, 1926. "This previously described fill surrounds and embeds all structural mem- -sion and providing Weight to the system at the same time. This system, which is shown in Figs. 1 and 2, is preferred when the air ducts (10) are constructed through the floor.

However, in some constructions it 1s preferredto have the air ducts through the suspended ceiling rather than through the floor in which case the modification shown in Figs. 3 and 4: may readily be used. This system diflers from theone' just described in that double suspended ceiling is necessary thereto, air ducts passing through the lower. of the two suspended ceilings. To this end vents (11) are placed over the air ducts. The air ducts themselves may be covered with a lattice work (12) and lined with a sound absorptive material The vents hav-- ing a series of funnels (16),.the dividing 1 0 cations of this second system is to have the air ducts pass through both the fioor and ceiling, the upper suspension separating the two, or to entirely omit either the upper or the lower suspension to suit job conditions.

This system of construction is particularly effective since it strikes at the root of sound transmission, obviating the transmission of sound through the various building members by imbedding these members in a flufi'y, flocculent incombustible insulating fill (19) having highly sound absorptive qualities, so rendering them inert to sound transmission, the fill also eliminates the drum or cushion action of so-called dead air spaces and at the same time provides the necessary weight. The arrangement of the structural members, the retaining plaster base consisting preferably of plaster board and the previously described insulating fill provide rigidity-the fluffy, flocculent property of the fill absorp tion. While the weight of the construction is not excessive, it is suflicient in itself to render considerable aid against sound transmission as the heavy system will not readily vibrate.

The use of a fireproof insulating fill surrounding and imbedding all members in place of highly inflammable absorptive fibrous. felts, blankets and pads, and the use of fireproof gypsum board for plaster base and gypsum board or tile for plenum chamber floor, renders this entire system highly fire resistant which is a very important factor in public buildings, such as theaters, schools, auditoriums, etc. making this system highly deslrable to meet present needs for sound insulation.

Having thus described my invention What I claim is:

1. A system of sound insulated construction for suspended ceilings, comprising a plurality of parallel ceiling members, metallic suspension connectors adapted to susend one ceiling member from a second memer, and a dry, fluffy, pulverulent, non-combustible, insulating fill between said ceiling members surrounding said connectors and adapted to prevent the passage of sound from one ceiling member to the other.

2. In a sound insulated ceiling construction, a horizontally supported floor member, a ceiling member supported below said floor member in parallel, spaced relation, said ceiling member being formed of a plurality of substantially parallel panels, supporting framework between said panels, suspension members connecting said framework to said floor member, and a dry, flutfy, pulverulent, non-combustible, insulating filling material between said panels and surrounding said framework.

3. In a sound insulated ceiling construction, floor and ceiling members in parallel spaced relation forming a plenum space therebetween, an air opening beingprovided through one of said members and connected with said plenum space, means for suspending said ceiling member from said floor member, said ceiling member being c'om osed of a plurality of panels in spaced para lel relation, and a dry flufi'y pulverulent, non-com bustible, insulating filling material between said panels.

4. In a sound insulated ceiling construction, floor and ceiling members inparallel, spaced relation forming a plenum space therebetween, an air opening being provided through one of said members and connected with said plenum space, means for suspending said ceiling member from said floor member, said ceiling member being composed of a plurality of panels in spaced parallel relation, and a sound insulating material positioned between said panels.

In witness whereof, I have hereunto subscribed my name.

BRUNO E. BALDUF. 

